(2020年9月23日更新)


クリイロニガイグチTylopilus castanoides Har. Takah., Mycoscience 43(5): 402 (2002)
   肉眼的特徴: 傘は径 30-80 mm, 最初半球形, のち平らに近い饅頭形〜ほぼ平開し, 縁部
は最初内側に巻く; 表面は乾性, 密綿毛状, 時に微細な亀裂を生じ, 幼菌から成菌に至るまで
傘全体が一様に赤褐色〜栗褐色を呈し, 老成するとやや青紫色を帯びる場合がある. 肉は厚
さ 10 mm, 固くしまり, 白色, 不変色または空気に触れると次第に淡い赤褐色を帯びる; 特別な
味や臭いはない. 柄は 50-110×7-17 mm, ほぼ上下同大または下方に向かってやや太くなり, 
中心生, 中実; 表面は乾性, 上部は表面と同色の微細な小鱗片に被われ, 下部は密綿毛状,  
平坦, 網目を欠き, 全体に傘と同色; 根本は類白色の密綿毛状菌糸体に被われる. 管孔は厚
さ 5-15 mm以下, 柄の周囲において陥入し, 幼時白色, のち帯紅色, 空気に触れても変色しな
い; 孔口は小型 (2-3 per mm), 類角形, 管孔と同色, 傷つけても変色しない
  顕微鏡的特徴: 担子胞子は 9-11(-13)×3.5-4μm, 長楕円形, イグチ型, 平坦, 帯紅色, 厚
壁. 担子器は 30-42×9-12.5μm, こん棒形, 4胞子性. 偽担子器はこん棒形. 縁シスチジアは
群生し, 13-25×4-6μm, 類こん棒形〜類円柱形, 平坦, 無色, 薄壁. 側シスチジアは散生し, 狭
紡錘形, 平坦, 無色, 薄壁. 子実層托実質はイグチ亜型. 傘の上表皮層は毛状被を形成する; 
末端細胞は円柱形, しばしば頂部は微突形になり, 幅 4-7μm, 赤褐色の粒状色素に厚く被覆
され, 薄壁. 傘実質の菌糸は緩く錯綜し, 円柱形, 幅 4-11μm, 無色, 薄壁. 柄の表皮は平行菌
糸被; 柄シスチジアは 20-45×4-7μm, 群生, 直立し, 円柱形, 平坦, 赤褐色の粒状色素に厚
く被覆され, 薄壁. 柄の実質は縦に沿って配列した円柱形の菌糸 (幅 4-10μm)からなり, 無
色, 薄壁. 全ての組織において菌糸はクランプを欠く.
  供試標本: KPM-NC0008776 (基準標本), Ageo-shi, Saitama-ken, Sept. 14, 2001, coll. S.
Uehara; Mt.Takao, Hachiouji-shi, Tokyo, Aug. 12, 1985, coll. H.Takahashi; the same place, Aug. 
4, 1998, coll. W.Ikeda & H.Takahashi.
  コメント: Section Oxydabiles に属し, 栗褐色の傘と柄からなる中〜大型の子実体を形成し,
肉は不変色または空気に触れると徐々に淡い赤褐色に変わり, 苦みはない. チャニガイグチ
Tylopilus ferrugineus (Frost) Singer に似るが, クリイロニガイグチの柄は表面と同色の小鱗片
に被われ,網目を欠く点で容易に区別できる.ブナ科を中心とする広葉樹林内地上に発生. 分
布は日本 (東京, 埼玉, 兵庫). 標本は神奈川県立生命の星・地球博物館の標本庫(KPM)に登
録, 収蔵されている.
  本種はマレーシア産 Boletus brunneirubens Corner に極めて類似しており, 両種の区別に
ついては今後再検討を要する. 
  フモトニガイグチの原記載および本郷博士による着色原図はクリイロニガイグチと全く色が
異なり, 苦みを有し, コビチャニガイグチにやや似ていると記載されている. しかし傘と柄が帯紫
赤褐色を帯び, 幼菌に苦みがあり, 成菌になると無味になる場合があるとも言われており, この
ような子実体の色と味の違いについては顕鏡データに関するタイプ標本の比較並びに地域別
の追加標本による形質の安定性を精査する必要がある.

参考資料:
関西菌類談話会会報35号2017.9


Tylopilus castanoides Har. Takah., Mycoscience 43(5): 402 (2002)
  Pileus 30-80 mm in diameter, at first hemispherical, becoming broadly convex to nearly 
plane in age, with inrolled then straight margin; surface dry, tomentose, sometimes finely 
areolate to conspicuously rimose in age, evenly colored reddish-brown (9D7-8, 9E7-8, or 9F7
-8,). Flesh up to 10 mm thick, firm, white, unchanging or gradually rufescent when cut; odor 
and taste indistinct. Stipe 50-110×7-17 mm, subequal or somewhat enlarged toward the 
base, central, terete, solid; surface dry, minutely scurfy-punctate above, tomentose below, 
smooth, not reticulate, entirely concolorous with the pileus; base covered with whitish 
mycelial tomentum. Tubes 5-15 mm deep, depressed around the stipe, white when young, 
dull pinkish in age, unchanging; pores small (2-3 per mm), subcircular, concolorous, 
unchanging. 
  Basidiospores 9-11(-13)×3.5-4μm [Q = length/breadth: 2.60-2.75, n = 20 spores per 
two specimens], inequilateral with a shallow suprahilar depression in profile, oblong ellipsoid in 
face view, smooth, pinkish, thick-walled. Basidia 30-42×9-12.5μm, clavate, four-spored. 
Basidioles clavate. Cheilocystidia gregarious, 13-25×4-6 μm, subclavate to subcylindrical, 
smooth, hyaline, thin-walled. Pleurocystidia scattered, narrowly ventricose- fusiform, 
smooth, hyaline, thin-walled. Hymenophoral trama parallel to each other, not divergent; 
elements similar to those of the pileitrama. Pileipellis a trichodermium of vertically and 
compactly arranged elements, heavily encrusted with reddish-brown, granular pigments that 
are completely dissolved in NH.OH, thin-walled; terminal cells 4-7 μm wide, cylindrical, often 
with mucronate apices. Pileitrama of cylindrical, loosely interwoven hyphae 4-11μm wide, 
smooth, colorless, thin-walled. Stipitipellis a cutis of parallel, repent hyphae 2.5-5 μm wide, 
cylindrical, colorless or thinly encrusted with reddish-brown pigments, thin-walled; 
caulocystidia 20-45×4-7 μm, numerous, erect, cylindrical, heavily encrusted with reddish-
brown, granular pigments that are completely dissolved in NH.OH, thin-walled. Stipe trama 
composed of longitudinally running, cylindrical cells 4-10 μm wide, unbranched, smooth, 
colorless. Clamps absent. 
  Known distribution: Japan (Saitama, Tokyo). 
  Habitat: Solitary to scattered, on ground in Carpinio-quercion forests, August to 
September, not common. 
  Specimens examined: KPM-NC0008776 (holotype), Ageo-shi, Saitama-ken, Sept. 14, 
2001, coll. S.Uehara; Mt.Takao, Hachiouji-shi, Tokyo, Aug. 12, 1985, coll. H.Takahashi; the 
same place, Aug. 4, 1998, coll. W.Ikeda & H.Takahashi. 
  Japanese name: Kuriiro-nigaiguchi (first collected and named by Mr.Minoru Aoki). 
  Notes: This species is characterized by its medium to large, reddish-brown basidiomata, 
the white, unchanging or gradually rufescent flesh, the minutely scurfy-punctate, not 
reticulate stipe, the cylindrical, often mucronate terminal elements of the pileipellis which 
are heavily encrusted with reddish brown, granular pigments, and the habitat in Carpinio-
quercion forests. Its white, rufescent flesh and its white then pinkish pores suggest that this 
species belongs in the section Oxydabiles Singer of the genus Tylopilus as defined by Singer 
(1986). 
  Within this section, Malaysian Boletus brunneirubens Corner (Corner 1972) appeared to 
be closely allied with this species. The Malaysian taxon differs in having a strong odor, a 
fawn ochraceous, slightly reticulate stipe, and clavate to ventricose cheilocystidia. The 
reddish-brown pileus and stipe and rufescent flesh of Tylopilus castanoides are also 
comparable with North American Tylopilus ferrugineus (Frost) Singer (Bessette et al. 2000; 
Snell and Dick 1970) and Tylopilus humilis Thiers (Thiers 1966, 1975). Tylopilus ferrugineus
differs in having a finely reticulate stipe and not heavily incrusting pileipellis elements. 
Tylopilus humilis is distinct in forming a poorly developed, short, often excentric stipe, non-
incrusted pileipellis elements, and mucronate caulocystidia.


Figs. 1.Tylopilus castanoides.
A Basidiospores. B Basidia and basidiole. C Cheilocystidia. D Pleurocystidia.
E Elements of the pileipellis. F Caulocystidia. All figures from the holotype. Bars 10µm.



Fig. 2. Basidiomata of Tylopilus castanoides.
Mt.Takao, Tokyo, Aug. 1998 (paratype)
1998年8月8日 東京都高尾山(従基準標本)


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